Browse
Submit Data
Databases
API
Help

Dataset Information

34 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Direct catalytic enantio- and diastereoselective ketone aldol reactions of isocyanoacetates.

ABSTRACT: A catalytic asymmetric aldol addition/cyclization reaction of unactivated ketones with isocyanoacetate pronucleophiles has been developed. A quinine-derived aminophosphine precatalyst and silver oxide were found to be an effective binary catalyst system and promoted the reaction to afford chiral oxazolines possessing a fully substituted stereocenter with good diastereoselectivities and excellent enantioselectivities.

SUBMITTER: de la Campa R

PROVIDER: S-EPMC4678506 | biostudies-literature | 2015 Apr

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Direct catalytic enantio- and diastereoselective ketone aldol reactions of isocyanoacetates.

de la Campa Raquel R Ortín Irene I Dixon Darren J DJ

Angewandte Chemie (International ed. in English) 20150303 16

A catalytic asymmetric aldol addition/cyclization reaction of unactivated ketones with isocyanoacetate pronucleophiles has been developed. A quinine-derived aminophosphine precatalyst and silver oxide were found to be an effective binary catalyst system and promoted the reaction to afford chiral oxazolines possessing a fully substituted stereocenter with good diastereoselectivities and excellent enantioselectivities. ...[more]

PMID: 25735645

Similar Datasets

Catalytic diastereoselective petasis reactions.

Project description:Multicomponent Petasis reactions: the first diastereoselective Petasis reaction catalyzed by chiral biphenols that enables the synthesis of syn and anti ?-amino alcohols in pure form has been developed. The reaction exploits a multicomponent approach that involves boronates, ?-hydroxy aldehydes, and amines.

| S-EPMC4673970 | biostudies-literature

Managing the retro-pathway in direct catalytic asymmetric aldol reactions of thioamides.

Project description:Thioamides are the preferred pronucleophiles for direct catalytic asymmetric aldol reactions in the context of soft Lewis acid/hard Brønsted base cooperative catalysis. In-depth investigation of this proton-transfer catalysis, which is virtually in equilibrium, revealed that the prominence of the retro-aldol reaction depended on the substrate combination. The retro-aldol reaction is a serious issue in direct aldol reactions because the product distribution, including enantiomers and diastereomers, is governed by thermodynamic parameters, and the aldol products are obtained in much lower stereoselectivity compared with the kinetically controlled process. Herein we report the beneficial effect of an additive with a functional group architecture similar to that of the aldol adduct that suppresses the retro-aldol reaction by competitively binding to the catalyst. Strategic use of the additive led to high stereoselectivity, even when the combination of substrates was prone to the retro-aldol reaction.

| S-EPMC6054082 | biostudies-other

Enantioselective catalytic transannular ketone-ene reactions.

Project description:Highly enantio- and diastereoselective transannular ketone-ene reactions are catalyzed by a new chromium(III) triflate tridentate Schiff base complex. Electronically unactivated keto-olefins undergo heteroene reactions at ambient temperature to afford enantioenriched bicyclic alcohols, common structural motifs in natural products. The kinetic resolution of a configurationally stable planar-chiral cyclodecenone is also described.

| S-EPMC3799808 | biostudies-literature

?-Siloxy-?-haloketones through highly diastereoselective single and double mukaiyama aldol reactions.

Project description:Double-action haloketones: A super silyl group enabled the first highly diastereoselective Mukaiyama aldol reactions of ?-chloro- and ?-fluoroketones with a wide range of aldehydes, providing anti-?-siloxy-?-haloketones. This process is compatible with one-pot double-aldol methodology and allows for rapid access to new halogen-modified polyketide fragments bearing up to four contiguous stereocenters.

| S-EPMC3874236 | biostudies-literature

Enantio- and Diastereoselective Synthesis of Homoallylic ?-Trifluoromethyl Amines by Catalytic Hydroalkylation of Dienes.

Project description:We describe a strategy for the enantio- and diastereoselective synthesis of homoallylic ?-trifluoromethyl amines by the catalytic hydroalkylation of terminal dienes. Trifluoromethyl-substituted isatin-derived azadienolate nucleophiles undergo ?-selective alkylation with a Pd-DTBM-SEGPHOS catalyst, which additionally promotes regioselective addition to the diene and delivers products in up to 86% yield, 10:1 dr, and 97.5:2.5 er.

| S-EPMC7079280 | biostudies-literature

A general diastereoselective catalytic vinylogous aldol reaction among tetramic acid-derived pyrroles.

Project description:A catalytic diastereoselective aldol reaction has been developed for N1-arylated/C2-O-silylated/C3-methylated and brominated/C4-O-methylated pyrroles in its reactions with various aldehydes. Syn adducts emerge with regard to the vicinal nitrogen and oxygen heteroatom substituents. The N1-aryl residue undergoes oxidative cleavage, and the C3-bromine atom undergoes palladium-mediated coupling reactions, both without disturbing the newly created stereocenters.

| S-EPMC4156244 | biostudies-literature

Enantioselective direct aldol reactions catalyzed by L-prolinamide derivatives.

Project description:l-Prolinamides 2, prepared from l-proline and simple aliphatic and aromatic amines, have been found to be active catalysts for the direct aldol reaction of 4-nitrobenzaldehyde with neat acetone at room temperature. They give moderate enantioselectivities of up to 46% enantiomeric excess (ee). The enantioselectivity increases as the amide N-H becomes a better hydrogen bond donor. l-Prolinamides 3, derived from the reaction of l-proline with alpha,beta-hydroxyamines such that there is a terminal hydroxyl group, show more efficient catalysis and higher enantioselectivities. In particular, catalyst 3h, prepared from l-proline and (1S,2S)-diphenyl-2-aminoethanol, exhibits high enantioselectivities of up to 93% ee for aromatic aldehydes and up to >99% ee for aliphatic aldehydes under -25 degrees C. Model reactions of benzaldehyde with three enamines derived from the condensation of prolinamides with acetone have been studied by quantum mechanics calculations. The calculations reveal that the amide N-H and the terminal hydroxyl groups form hydrogen bonds with the benzaldehyde substrate. These hydrogen bonds reduce the activation energy and cause high enantioselectivity. Our results suggest a new strategy in the design of new organic catalysts for direct asymmetric aldol reactions and related transformations.

| S-EPMC395980 | biostudies-literature

Direct asymmetric Zn-aldol reaction of methyl vinyl ketone and its synthetic applications.

Project description:A direct catalytic asymmetric aldol reaction of methyl vinyl ketone is described using our dinuclear zinc catalyst. The obtained aldol adduct functions as a bifunctional building block by utilization of the vinyl functionality. For example, convergent fragment coupling methods have been demonstrated via highly diastereoselective cycloaddition of nitrile oxide after reduction into 1,3-diol or via cross-metathesis reaction.

| S-EPMC2535804 | biostudies-literature

Enantio- and diastereoselective conjugate borylation/Mannich cyclization.

Project description:Strategies to capitalize on enolate intermediates generated from stereoselective conjugate borylation to α,β-unsaturated carbonyl systems are surprisingly rare despite the ubiquity of Michael acceptors, and the potential to generate valuable scaffolds bearing multiple stereocenters. Herein, we report a mild and stereoselective copper-catalyzed conjugate borylation/Mannich cyclization reaction. This strategy is feasible with a broad range of Michael acceptors, and can be leveraged to generate versatile borylated tetrahydroquinoline scaffolds bearing three contiguous stereocenters. The synthetic potential of these complex heterocycles has been explored through a series of derivatization studies.

| S-EPMC8159378 | biostudies-literature

Enantio- and diastereoselective synthesis of syn-?-hydroxy-?-vinyl carboxylic esters via reductive aldol reactions of ethyl allenecarboxylate with 10-TMS-9-Borabicyclo[3.3.2]decane and DFT analysis of the hydroboration pathway.

Project description:An enantio- and diastereoselective synthesis of syn-?-hydroxy-?-vinyl carboxylate esters 3 via the reductive aldol reaction of ethyl allenecarboxylate (2) with 10-trimethylsilyl-9-borabicyclo[3.3.2]decane (1R) has been developed. Density functional theory calculations suggest that the allene hydroboration involves the 1,4-reduction of 2 with the 1R, leading directly to dienolborinate Z-(O)-8a.

| S-EPMC3849616 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data